According to the fast growth of semiconductor technology, many blocks and functions have been integrated on a chip as a System-On-Chip (SOC) technology. In the semiconductor technology, a monolithic transformer requires a significant amount of space. Moreover, the monolithic transformer requires a minimum of 50-μm spacing from other circuitry to prevent undesirable magnetic coupling or loss of magnetic flux. Accordingly, the total size of multiple transformers is large and increases manufacturing cost, chip size, and package size.